public synchronized boolean next(K key, V value) throws IOException {
setProgress(getProgress());
long beforePos = getPos();
boolean ret = rawIn.next(key, value);
if (ret) {
inputRecordCounter.increment(1);
inputByteCounter.increment(getPos() - beforePos);
}
return ret;
}
/**
* Handles the degenerate case where serialization fails to fit in the in-memory buffer, so we
* must spill the record from collect directly to a spill file. Consider this "losing".
*/
@SuppressWarnings("unchecked")
private void spillSingleRecord(final K key, final V value) throws IOException {
long size = kvbuffer.length + partitions * APPROX_HEADER_LENGTH;
FSDataOutputStream out = null;
FSDataOutputStream indexOut = null;
final int partition = partitioner.getPartition(key, value, partitions);
try {
// create spill file
Path filename = mapOutputFile.getSpillFileForWrite(getTaskID(), numSpills, size);
out = localFs.create(filename);
// create spill index
Path indexFilename =
mapOutputFile.getSpillIndexFileForWrite(
getTaskID(), numSpills, partitions * MAP_OUTPUT_INDEX_RECORD_LENGTH);
indexOut = localFs.create(indexFilename);
// we don't run the combiner for a single record
for (int i = 0; i < partitions; ++i) {
IFile.Writer writer = null;
try {
long segmentStart = out.getPos();
// Create a new codec, don't care!
writer = new IFile.Writer(job, out, keyClass, valClass, codec);
if (i == partition) {
if (job.getCombineOnceOnly()) {
Reducer combiner = (Reducer) ReflectionUtils.newInstance(combinerClass, job);
combineCollector.setWriter(writer);
combiner.reduce(
key,
new Iterator<V>() {
private boolean done = false;
public boolean hasNext() {
return !done;
}
public V next() {
if (done) throw new NoSuchElementException();
done = true;
return value;
}
public void remove() {
throw new UnsupportedOperationException();
}
},
combineCollector,
reporter);
} else {
final long recordStart = out.getPos();
writer.append(key, value);
// Note that our map byte count will not be accurate with
// compression
mapOutputByteCounter.increment(out.getPos() - recordStart);
}
}
writer.close();
// index record
writeIndexRecord(indexOut, out, segmentStart, writer);
} catch (IOException e) {
if (null != writer) writer.close();
throw e;
}
}
++numSpills;
} finally {
if (out != null) out.close();
if (indexOut != null) indexOut.close();
}
}
@SuppressWarnings("unchecked")
public synchronized void collect(K key, V value) throws IOException {
reporter.progress();
if (key.getClass() != keyClass) {
throw new IOException(
"Type mismatch in key from map: expected "
+ keyClass.getName()
+ ", recieved "
+ key.getClass().getName());
}
if (value.getClass() != valClass) {
throw new IOException(
"Type mismatch in value from map: expected "
+ valClass.getName()
+ ", recieved "
+ value.getClass().getName());
}
if (sortSpillException != null) {
throw (IOException) new IOException("Spill failed").initCause(sortSpillException);
}
try {
// serialize key bytes into buffer
int keystart = bufindex;
keySerializer.serialize(key);
if (bufindex < keystart) {
// wrapped the key; reset required
bb.reset();
keystart = 0;
}
// serialize value bytes into buffer
int valstart = bufindex;
valSerializer.serialize(value);
int valend = bb.markRecord();
mapOutputByteCounter.increment(
valend >= keystart ? valend - keystart : (bufvoid - keystart) + valend);
if (keystart == bufindex) {
// if emitted records make no writes, it's possible to wrap
// accounting space without notice
bb.write(new byte[0], 0, 0);
}
int partition = partitioner.getPartition(key, value, partitions);
if (partition < 0 || partition >= partitions) {
throw new IOException("Illegal partition for " + key + " (" + partition + ")");
}
mapOutputRecordCounter.increment(1);
// update accounting info
int ind = kvindex * ACCTSIZE;
kvoffsets[kvindex] = ind;
kvindices[ind + PARTITION] = partition;
kvindices[ind + KEYSTART] = keystart;
kvindices[ind + VALSTART] = valstart;
kvindex = (kvindex + 1) % kvoffsets.length;
} catch (MapBufferTooSmallException e) {
LOG.info("Record too large for in-memory buffer: " + e.getMessage());
spillSingleRecord(key, value);
mapOutputRecordCounter.increment(1);
return;
}
}
public void collect(K key, V value) throws IOException {
reporter.progress();
out.write(key, value);
mapOutputRecordCounter.increment(1);
}
